v2writable: support "barrier" operation to avoid reforking

Stopping and starting a bunch of processes to look up duplicates
or removals is inefficient.  Take advantage of checkpointing
in "git fast-import" and transactions in Xapian and SQLite.

1 files changed, 12 insertions, 0 deletions

diff --git a/lib/PublicInbox/SearchIdxPart.pm b/lib/PublicInbox/SearchIdxPart.pm
index 6d8cb2a7..dd7ace67 100644
--- a/lib/PublicInbox/SearchIdxPart.pm
+++ b/lib/PublicInbox/SearchIdxPart.pm
@@ -49,6 +49,11 @@ sub partition_worker_loop ($$$) {
                 } elsif ($line eq "close\n") {
                         $self->_xdb_release;
                         $xdb = $txn = undef;
+                } elsif ($line eq "barrier\n") {
+                        $xdb->commit_transaction if $txn;
+                        $txn = undef;
+                        print { $self->{skeleton}->{w} } "barrier $part\n" or
+                                        die "write failed to skeleton: $!\n";
                 } else {
                         chomp $line;
                         my ($len, $artnum, $oid, $mid0) = split(/ /, $line);
@@ -81,4 +86,11 @@ sub atfork_child {
         close $_[0]->{w} or die "failed to close write pipe: $!\n";
 }
 
+# called by V2Writable:
+sub barrier {
+        my $w = $_[0]->{w};
+        print $w "barrier\n" or die "failed to print: $!";
+        $w->flush or die "failed to flush: $!";
+}
+
 1;